German intelligence agencies and police have granted asylum to roughly 1,000 refugees in exchange for sensitive information, often by means of “intervention” in the decisions of the national immigration authority, the government has said.

Intelligence services and the federal police have granted asylum to almost 1,000 migrants over the past 15 years, the government’s official response to a parliamentary request for information said. According to the paper, between 1958 and 2013 Germany’s main intelligence agency, the BND, operated a so-called Main Questioning Facility (HBW) which was in charge of collecting specific intelligence from migrants entering the country.

Many “questioning” sessions involved US officers from the Pentagon’s Defense Intelligence Agency (DIA) and the National Security Agency (NSA), though respondents were not aware of the officials’ real identities. Other German agencies such as the federal police, customs service and regional domestic intelligence authorities were also said to have access to recruiting their own informants among migrants.

The HBW would then ask the Federal Office for Migration and Refugees (BAMF) to grant asylum to each migrant deemed suitable to become a BND source. Such requests, described in the paper as “interventions,” were justified by the claim that the migrants would face imminent death or torture if forced to return to their countries of origin.

Most informants came from the Middle East – with the peak figures in 2001-2002 after 9/11 – followed by nationals of post-Soviet countries, Africa, Asia and the Balkans, the document says. Notably, the immigration service rejected two asylum “interventions” in 2002, even after those informants had been recruited by the BND.

The BND’s “questioning facility” allegedly maintained close contact with both the DIA and NSA, allowing them to access intelligence collected from migrants. In several cases, the intelligence was used to identify targets for US drone strikes in the Middle East and Africa. The government document described the information as extremely valuable for military use.

But Martina Renner, an MP from Die Linke party who co-authored the request for information, told Die Zeit newspaper that “the quality of information obtained could be very questionable.” She argued that refugees – keen to get permission for their stay in Germany – would say anything they believed their questioners wanted to hear.

One of the most dramatic examples, Renner said, was the DIA agent codenamed “Curveball” (real name Rafid Ahmed Alwan al-Janabi), who initially defected from Iraq to Germany in 1999.

His fake testimonies about Saddam Hussein’s weapons of mass destruction program were used by the US as a rationale to invade Iraq in 2003, despite both the BND and British MI6 questioning the authenticity of the claims.

Although the BND’s questioning facility was officially closed in 2013, the recruitment of agents from among migrants did not stop. Germany’s domestic intelligence, the Federal Service for the Protection of the Constitution, contacts asylum seekers on a “case-by-case” basis, while the BND still monitors refugee hostels to look for prospective informants, Die Zeit reported.